Panels of a variety of structural designs for use in siding or covering the exterior walls of buildings have been known for a long time. These siding elements are generally constructed of a metal, typically aluminum, or a thermoplastic material. In the latter case, poly(vinyl chloride) or "PVC" is typically employed because of its superior resistance to weathering.
In order to simulate the clapboard wooden siding commonly used in home construction, metal or thermoplastic siding elements are typically constructed with so-called "declinations" or downwardly and outwardly extending flat portions which are connected by horizontal shoulders. Additionally, structural features are provided on the siding elements including an uppermost nailing strip and elements which permit interlocking panels above or below one another. These siding panels are typically supplied commercially in so-called "two-wide" and "three-wide" versions. In two-wide panels, there are two declinations: an upper declination and a lower declination, connected by a short horizontal shoulder. Three-wide siding panels have three such declinations, with horizontal shoulder regions connecting the upper to the middle declination and another horizontal shoulder connecting the middle declination to the lowest declination.
The rear or building-facing view of one such siding panel 100, which finds current wide use in the building trades, is illustrated in FIG. 1 in rear perspective view. The panels are commercially provided in long sections, typically in lengths of 12 feet (3.66 meters) to 16 feet (4.88 meters). In FIG. 1, the center portion of the illustrated panel has been removed to show only the first 102 and second 104 end regions of the panel.
The panel 100 comprises a first upper 106 and a second lower 108 substantially flat declination region. The upper declination 106 is connected to the lower declination 108 by substantially horizontal shoulder region 110. A similar shoulder region 112 is attached to lower declination 108. The shoulder 112 attached to the lower declination 108 is further provided with a re-curved edge region 114 which extends upwardly and slightly inwardly toward the back or inside face of lower declination 108. This re-curved edge of lower shoulder 114 is designed to fit into a substantially S-shaped recurve on the next lower panel in a manner shown in FIG. 4 and further described below.
The upper declination 106 of the siding panel 100 is surmounted by an integral nailing strip and clamping region. The nailing strip and clamping region of the siding panel is made up of an upper flat nailing strip 116 which is perforated by nailing holes 120 As the flat nailing strip merges with the upper declination 106, the panel forms a clamping region 118 which forms, in side view, a substantially S-shared recurve 122. The lower end of this S-shaped clip region 118 merges with the upper declination 106. The nailing strip 116 and S-shaped recurve portion of the first 102 and second 104 ends of panel 100 are trimmed at the factory to form first 124 and second 126 cut-outs, respectively, in the upper nailing strip 116 and S-shaped recurve 122. Similar cut-outs 128 and 130 are made in the lower shoulder region 112 and its recurve portion 114.
When siding panels of this type are applied to a building, a special initial nailing strip or "starter strip" shown in FIG. 2 is first attached at the bottom of the wall being sided. This starter strip 200 comprises the nailing strip portion 216, an S-recurve portion 222, and nail holes 220 of a siding panel, but lacks the declination portions.
FIG. 3 depicts, in cross-sectional side view, how a first siding panel of the type shown in FIG. 1 is attached to a building wall. Following attachment of the starter strip 200, of FIG. 2, to the building wall 310 by means of nails 306, the recurve 114 of the lower shoulder 112 of a first siding panel is inserted into the S-shaped recurve 222 of the starter strip. The panel is pulled firmly upward, and nailed (through nailing holes 120 in its top nailing strip 116, not shown in FIG. 3) to the building wall 310. Subsequent siding panels are similarly attached to the wall of the building, proceeding upwardly, clipping the lower shoulder recurve 114 of each successive panel into the upper S-shaped clamping region 118 of the siding panel immediately below.
This arrangement can be seen in FIG. 4 where a cross-sectional side view of two vertically adjacent siding panels are shown fastened to the wall of a building. In FIG. 4, the lower declination 108a of an upper siding panel and the upper declination 106 of a lower siding panel, both of the type shown in FIG. 1, are shown fastened to a building wall 310. The lower shoulder region 112a of the upper panel, with its recurve 114a, is shown clipped into the S-recurve 122 of the lower panel. Both the nails holding the starter strip and the nails securing the siding panels to the building wall are not completely driven into the building wall 310 through the elongated nail holes. This permits lateral thermal expansion and contraction of the siding panels after being mounted to the building wall.
As the siding is laid up, the lateral joints between adjacent sets of attached siding panels are staggered, rather than being vertically aligned, to provide a pleasing appearance. Typically, the nailing strips and bottom declination shoulders of commercially available siding panels are notched during manufacture to assist in the side-by-side interlocking of adjacent panels. These cut-outs can be seen as elements 124, 126, 128 and 130 in FIG. 1. By clipping the notched lower shoulder of one panel and its recurve of each siding panel into the S-recurve clamp of the panel (or starter strip) immediately adjacent below, horizontally adjacent siding panels can be overlapped making use of these cut-outs. This arrangement can be seen in FIG. 5 where two siding panels, 102 and 102a of the type depicted in FIG. 1 are shown overlapping.
In FIG. 5, for purposes of illustration, the two panels are shown as abbreviated in length. Panel 102a is shown overlapped behind panel 102. The terms "front" and "rear" or "in front of" or "behind," "up" and "down," "inwardly" and "outwardly" with regard to the siding panels or elements thereof, as used throughout this specification and the appended claims refer, respectively, to the faces and orientation of the panels and panel elements once the panels are applied to a building.
In the following discussion, reference numerals without prime marks are used in referring to elements of panel 102 and the same reference numerals with prime marks are used for corresponding elements of panel 102a. As can be seen in FIG. 5, the overlap is achieved by inserting the cut-out 128' in the lower left-hand rear face of panel 102a into the cut-out 130 in the lower right-hand rear -ace of panel 102. In a similar manner, the cut-out 126 in the nailing strip and S-recurve at the upper right-hand face of panel 102 is inserted into the cut-out 124' in the upper left-hand rear face of panel 102a. As a result of this overlap, a portion of cut-out 126 in panel 102 is clipped into the S-recurve at the top of panel 102a. During installation of the siding, the two panels are overlapped, retaining a gap 550 in the cut-outs between horizontally adjacent panels to permit thermal expansion and contraction of the panels. The overlap is indicated by the dotted line in FIG. 5 which represents the hidden rearward right-hand edge 560 of panel 102.
This prior art combination of lateral overlapping of horizontally adjacent siding panels, and vertical interlocking and nailing (in the manner described above) results in the firm attachment of each siding panel to a building wall at the upper and lower extremities of each panel. However, this arrangement does not provide for adequate interlocking of the intermediate declinations of one siding panel to those of a panel next horizontally adjacent. The problem exists with two-wide siding panels, and is considerably exacerbated with three-wide and wider siding panels. There are four undesirable effects of this lack of interlocking: first, gaps in the declinations of one siding panel and those immediately horizontally adjacent are unsightly. Second, wind can catch and pull off a siding panel if gaps exist between the declination of one panel and those of its neighbor. Third, a loose fit between the declinations of one panel and those of a horizontally adjacent panel permit rain to enter and cause water damage and rot to the underlying wooden structure. Finally, insect infestation behind the mounted siding can cause bulging in the siding if gaps in the declination overlap permit insect entry. There is thus a strong need in the building trades for an improved type of vinyl siding which overcomes these problems.